Gear-tooth grinder



March 29?, 1927.,

A. L. WlLDEER GEAR TOOTH GRINDER Filed Aug. 2, 1923 3 Sheets-Sheet 1 IN V EN TOR ATTORNEY @LWLMM March 29', 1927.

A. L. WILDER GEAR TOOTH GRINDER Filed Ana. 2, 1923 3 Sheets-Sheet 2 IN V EN TOR a. L. Wilde/z,

ATTORNEY mzmw Mm'ch 29,1927

A..L. WILDER GEAR TOOTH GRINDER M/KZ A TTORNE Y Patented Mar. 29, 1927.

ARTHUR L. WILDER, OF NETHERSFIELD, CONNECTICUT, ASSIGNOR TO PRATT & WHIT- NEY COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

GEAR-TOOTH GRINDER.

Application filed August 2, 1923.

This invention relates to gear generating machines and in particular to an improved form of generating machine for gear tooth curves of involute form preferably having two oppositely disposed grinding wheels or tools adapted to engage opposite sides of different teeth.

An object of the present invention is to provide a construction of gear tooth generating machine enabling a large number of identical gears to be rapidly ground in a relatively simple and semi-automatic machine.

Another object of the invention is to pro vide a construction permitting a wide range of adjustment of the parts of the machine adapting the machine for widely different types and sizes of spur gears.

Another object of the invention is to provide means for accomplishing a particular movement of the gear bein ground relative to the cutting surfaces of the wheels or tools, this movement simulating a short rolling action of a gear along a rack so that the teeth of the gear will correctly engage the cutting wheels or tools, these movements of the gear blank being so proportioned that they generate involute tooth curves on the blank.

Preferably these movements are accomplished by improved actuating means for the work blank to effect the movements of the gear blank relative to the wheel or tool. These comprise a rotating cam member adapted to oscillate and reciprocate an arm, the combined movements of this arm being utilized to actuate the gear blank in a closed path.

Another object of the invention is to mount the actuating cam and the parts for actuating the Work spindle upon a member having a limited free movement so that this member may be advanced during operation of the machine to effect a feeding movement of the blank relative to the cutting wheels or tools.

Another object of the invention is to provide a machine of the general type disclosed and claimed in the patent to Tanner et al No. 1,598,173 granted August 31, 1926.

In the above-mentioned application, the work spindle with the gear to be ground thereon is rotated by special driving means and those rotating means are utilized to actuate the blank about in a closed path. In

Serial No. 655,305.

the present invention no special rotating means are required for the work spindle, instead, a rotating cam is provided which actuates the Work spindle through an oscillating and reciprocating arm. By means of the movements obtained from this arm, the work spindle is actuated in a closed path and a master gear thereon is moved into and out of engagement with oppositely disposed racks. Also, while the master gear is in mesh with each of the racks, the movement of the arm is such that it rolls the master gear along one of the racks. As the gear to be ground is rotated and moved bodily with the master gear, its movements and positions are such that the gear is rolled past the cutting surface of the wheel or tool, so that tooth curves of involute form will be generated.

A principal object of the present inven tion therefore is to provide improved and simplified actuating means to effect the above described movements of the gear blank whereby involute curves may be formed on the teeth of a blank.

With these and other objects in view, my invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanyin drawings.

In the accompanying drawings annexed hereto and forming a part of this specification, 1 have shown my invention embodied in a grinding machine for spur gears of relatively small size but it will be understood that certain features of the invention can be otherwise embodied and adapted for gears of other types and that the drawings are not to be construed as defining or limiting the scope of this invention, the claims appended to this specification being relied upon for that purpose.

In the drawings:

Figure 1 is a plan View of the complete machine.

Fig. 2 is a vertical sectional view taken substantially on line 22 of Fig. 1.

Fig. 8 is a plan view of a portion of the machine showing the relative positions of the blank and the abrasive wheels.

Fig. 4 is a horizontal view in section on line H of Fig. 2 showing the parts for controlling the position of the gear blank spindle.

Fig. 5 is a detail view of the actuating cam and a diagram showing the limits of movement of the arm carrying the master gear.

6 is a detail sectional view on line 66 of Fig. 2 of the parts at the forward end of this arm, and

Fig. 7 is a sectional view taken on line 77 of Fig. 6.

In the above mentioned drawings, I have shown but one embodiment of the invention which is now deemed preferable but it is to be understood that changes and modifications may be made within the scope of the appended claims to adapt the mechanism for other types or sizes of gears and for other purposes without departing from the spirit of the invention.

Briefly, my invention in its broadest aspect comprises the following principal parts: First, a base; second, a spindle adapted to be moved about: in any direction while its axis is maintained vertical; third, a master gear thereon; fourth, means on the spindle adapted to support and rotate a work arbor; fifth, a slide adapted to have limited movements in one direction; sixth, an arm mounted to move in all directions; seventh, a cam adapted to actuate the one end of the arm in a predetermined path; eighth, means connecting said arm to the vertical spindle so that the master gear on said spindle will engage oppositely disposed rack teeth mounted on the slide when the arm is actuated by the cam; ninth, one or more heads having abrasive wheels or other suitable cutting tools thereon adapted to be adjusted relative to the gear blank and adapted to engage the gear teeth of said blank upon one of their radial surfaces.

Referring more in detail to the figures of the drawings, I provide a base 10 having a vertically disposed support or column 11 rigidly mounted thereon and providing suitable bearings for a rotatable spindle or shaft 12 preferably mounted vertically therein. This shaft or spindle 12 is adapted to be actuated in a closed path of a particular form and simultaneously rotated by means presently to be described. In order to per mit movement of the work supporting and rotating spindle 12 in any direction while its axis is retained in a vertical position, this member is mounted at the free extremity of a pair of swinging arms 12 and 1d. The swinging arms permit the spindle 12 to be moved about in any direction while maintaining its axis always extending in the same direction.

On the upper horizontal surface of the base 10 are provided wheel mountings 16 which preferably may be angular-1y adjusted thereon about fixed axes. These wheel mountings 16 have mounted thereon slides 17 and 18 one above the other and movable in directions at right angles to each other, the

upper one 18 of which carries the wheel spindle and wheel rotatably mounted in suitable bearings. Also mounted on, one of these slides 17 is a small motor 19 for rotating the wheel spindle 20 and wheel 21. As the construction of the wheel heads, the form of abrasive wheels and their method of adjustment relative to the work being ground are, or may be, similar to the corresponding means in the above mentioned patent, it will be unnecess to further described these parts. Sumo-e it to say that two of these wheel heads 18 preferably may be provided symmetrically disposed on opposite sides of the work supporting and rotating spindle 12. Also the construction is such that adjustment of one of the slides, namely 17, advances its wheel 21 directly toward or from the work spindle 12 in a direction parallel to the abrasive surface of the wheel. Adjustment of the other slide, namely 18, advances its wheel 21 in a direction parallel to the axis of the wheel spindle.

Mounted within or upon the base 10 so that it is disposed horizontally is a slide 25 prefe "ably guided as shown upon oppositely disposed ball bearings 26 to permit ready l'tClLJl'OLltlOll in either direction. Preferably also this side 25 is suspended by flexible or resilient steel strips 27 at the forward and rearward parts of the machine, the upper ends which are permanently fastened to statioimry parts of the machine attached to the base 10 and to the column 11 and their lower ends are attached to the slide 25. By means of these resilient connections 27, the slide 25 permitted a free movement forward or rearward between restricted limits while being retained always in horizontal position.

In order to actuate this slide forward and rearward for the purpose of feeding the gear blank A relative to the wheels 21 during the grinding operation, mechanism is provided comprising a pivoted lever 30, the upper end of which is attached to a projection on the slide 25 as shown in Fig. 2. An intermediate portion of this lever bears against a bar 31 which may be adjusted to initially set the slide in operative position for the particular gears being ground, this bar forming a fulcrum for the lever 30. The lower end of this lever is adapted to engage a spiral cam 32 so that rotation of this cam will cause a feeding movement of the gear blank toward the abrasive wheels. he means for driving this cam 32 and for stopping it at the end of its rotation form no part of the present invention so that a specific description of the n'ieclzanism for this purpose may be oi'nitted. The effect of rotation of the spiral cam 32 is to force the slide rearward a slight distance which caui-i-es the work blank A to be moved backward, together with its spindle 12, to a position to be more or less contacted with by the wheels. Also as soon as the cam 32 has completed one revolution, the slide 25 is returned to its initial forward position.

Mounted upon a vertical axis in suitable ball bearings 35 provided in the slide 25 is a rotatable shaft- 36. The lower end of this shaft is provided with a. helical gear 37 in mesh with another helical gear 38 on the rear end of a driving shaft 89. The helical gear 38 on the driving shaft 39 is preferably splined thereto or otherwise movable longitudinally therealong. The shaft 39 is preferably supported by bearings 40 projecting from the portion of slide 25 provided for supporting the vertical shaft 36. In this way, the driving connections for the vertical shaft 36 are not interrupted by forward or rearward movements of the slide 25.

A motor preferably mounted on a portion of the base 10 may be provided for operating the feed mechanism described above and also for rotating the vertical shaft 36. For this purpose a shaft 46 extending from the armature of the motor 1-5 through suitable change gearing 47, rotates the shaft on which the helical gear is mounted. Also driven from the same shaft 46 and through another pair of change gears 49 and suitable helical gears 50 is the shaft 51 for rotating the spiral cam 32 and is driven at a very slow speed. Preferably hand means may be provided to actuate the feeding mechanism which may be operated by the shaft 52 hav ing a hand wheel 53 thereon as shown. This shaft 52 may be connected to the cam shaft 51 through the gearing comprising a part of the helical gear 50.

At the upper end of this rotating shaft 36 is provided a cam 55 of particular form, the periphery of which is very accurately formed. The form of the cam 55 is shown clearly in Fig. 5 and is such that when rotated it gives a substantially rectilinear movement within a. closed path to the rear end of an arm 56 provided with a square opening 57 adapted to contact with this arm 55. The movement of the rear end of the arm 56 induced by-the cam is a rectilinear four-motion movement, the lateral as well as the forward and rearward movements being equal in extent. The forward end of the arm or lever 56 is provided with a roller 58 contacting on opposite sides with spring pressed plungers 59. This construction, shown in Fig. 6, is such that forward or rearward movement of the arm is permitted as well as its lateral movement. Intermediate the ends of this arm 56 is a circular opening within which fits a. ball bearing 60. The outer member of this bearing is forced into the opening formed in the arm 56 and the inner member is mounted on the extreme lower end of the work spindle 12.

'. It will be seen therefore that rotation of the actuating cam 55 will force the work spindle 12 to move forward and rearward an amount equal to the entire throw of the cam 55. The lateral movements of the rear end of the lever will effect a lateral movement to the work spindle which will be greatly reduced at the intermediate point at which bearing 60 is attached compared to its forward and rearward movement. This is for the reason that the spindle 12 is mounted at a point on the arm 56 near its forward end or fulcrum. The path of movement of the work spindle will therefore be substantially as indicated in Fig. 5 which, as shown, is of oblong form.

Mounted on opposite sides of the slide 25 directly above the opening in which the bearings 60 are mounted are short sections of racks 62 having rack teeth of correct size to engage teeth on a master gear 65 mounted on the work rotating spindle 12. This master gear 65 and the teeth of the rack 62 meshing therewith are of the same pitch as the gears adapted to be ground on the work arbor. Also the distance between the pitch lines of the oppositely disposed racks 62 is slightly greater than the outside diameter of the master gear 65 so that when the master gear 65 engages one rack 62 it is entirely disengaged from the opposite one.

As shown in Fig. 7, the master gear 65 on the spindle 12 is adapted to engage the racks 62 alternately as the spindle 12 is actuated in its path. These racks 62 are retained in recesses formed in a member 66 mounted on the slide 25. Directly below the racks 62 are strips 67, one being placed below each of the racks 62. These are adapted to be engaged by the outer ring of a ball bearing 68 mounted on and rotating with the spindle 12 and master gear 65. By means of these strips 67 and the bearing 68. the spindle is constrained to move in a straight line while the master gear 65 engages each of the racks.

The racks 62 are spaced apart so that while the master gear 65 is fully in mesh with one it is entirely clear from the other. \Vhile partly engaging one, however, it part- 1y engages the other, that is, there is no intermediate position when the master gear 65 is entirely free from both of the racks 62. At no point in the cycle of operation there fore is it possible for the master gear 65 and the parts on the spindle 12 to be freely rotated. These parts are always constrained to move within their closed path and simultaneously be rotated by their engagement of the master gear with the racks.

A gear A being ground and which is mounted on the work spindle 12 will be moved alternately into and out of engagement with the abrasive wheels 21. \Vhile the blank A is in engagement with one of the wheels 21, the master gear 65 on the 1 spindle 12 is being rolled relative to one of the racks 62 on the slide The abrasive wheel .21 there'l'ore will generate one side of one ot the teeth of the gear blank. The opposite wheel 21 when it is in engagement with the gear blank generates the opposite side of a tooth. Continued rotation of the gear blank A caused by the combined movements of the arm 56 and the rolling action of the master gear on the racks 62 advances successive teeth into engagement with the wheels. This is due to the fact that movement of the master gear 65 from one rack 62 to the other takes place after the blank has been rolled a distance equal to one or more circular pitches. The mechanism is therefore self-indexing as in the above referred to application.

It will be understood that the master gear 65 will correspond exactly in number of teeth and pitch with the gears to be ground. Also the racks 62 will be of suitable form to properly engage therewith. With the Wheels 21 properly located above the racks 62, they will engage the blank A as it is being in effect rolled along a rack. The radial cutting surfaces of the wheels 21 will therefore generate involute tooth curves upon the blank A.

In operation, as the cam 55 rotates, the arm 56 is oscillated so that it moves the master gear 65 into contact with one of the racks 62. Simultaneo sly the ball bearing is brought into contact with one of the straight edges 67. An additional slight oscillation of the arm 56 serves to retract one of the spring pressed plungers 59. Further rotative movement of the cam 55 advances the arm 56 until its oscillatory movement moves the master gear 65 toward the rack on the opposite side and retracts the opposite plunger 59. In this way, the arm 56 is always so hold that it resiliently retains the master gear 65 and the ball bearing 86 in contact with a rack and straight edge on one side of the slide 25.

hat I claim is:

1. A machine for enerating tooth curves of gears comprising in combination, a base, a cutting wheel thereon, a work supporting spindle adapted to be moved to any position While its axis is retained in parallel positions, a cam adapted to impart a four-way motion to one end of an arm, means to rotate said cam, means positioned at an inter mediate point of said arm adapted to engage said work spindle, and means to rotate said spindle simultaneously with its motion induced by said cam.

2. A. machine for generating tooth curves of gears comprising in combiantion, a base, a cutting wheel thereon, a work supporting spindle adapted to be moved to any position while its axis is retained in parallel positions, a cam adapted to impart a motion in a closed path to one end of an arm, means to rotate said cam, means positioned at an intermediate point of said arm in engagement with said work spindle, a gear on said work spindle, and means engaging said gear during portions of its movement whereby said spindle is given a rotat'ive movement simultaneously with its motion induced by said cam.

3. A gear tooth generating machine comprising in combination, a base, a cutting wheel thereon, vork supporting means comprising a spindle movable to any position while its axis extci'ids in the same direction, cam means to effect HHWG'A'IIQHt of said spindle in a closed path to engage a blank with said cutting tool, and means to feed said blank relative to said tool.

4:. A gear tooth generating machine com prising in combination, a base, a cutting wheel thereon, work supporting means comprising a spindle movable to any position while its axis extends in the same direction, an arm, means at one end thereof to move it in a closed path, means connecting said spindle to said arm, so that said spindle is moved about in a closed path, and supplementary means for rotating said spindle While being moved in said path.

5. A gear tooth gencrat-im machine com prising in con'ibination, a base, a cutting Wheel thereon, work supporting means comprising a spindle movable to any position While its axis extends in the same direction, an arm, means at one end thereof to move it in a closed path, means connecting said spindle to said arm so that said spindle is moved about in a closed path, and means to feed said work supporting means toward said cutting wheel during operation.

6. A gear tooth generating machine comprising in con'ibinatioi'i, a base, a cutting wheel thereon, work supporting means com prising a spindle movable to any position while its axis extends in the same direction, an arm, means at one end thereof to move it in a closed path, rotative means connecting said spindle to an intermediate point of said arm, a master gear of said spindle adapted to engage racks so that the spindle may be simultaneously rotated while being moved about, and resilient means for mounting said racks whereby they may be moved to advance the work support-ing means toward said cutting wheel.

7. A gear tooth generating machine comprising in con'ibination, a base, a cutting wheel thereon, work supporting means comprising a spindle movable to any position while its axis extends in the same direction, an arm, means at one end thereof to move it in a closed path, rotative means connecting said spindle to an intermediate point of said arm, a master gear or said spindle adapted to engage racks so that the spindle may be simultaneously rotated while being moved about, and cam operated means to advance said racks whereby the may be moved to advance the work supporting means toward said cutting wheel.

8. A gear tooth generating machine comprising in combination, a base, a cutting tool thereon, work supporting means comprising a spindle movable to any position while its axis extends always in the same direction, an arm for mounting the work spindle, means to actuate one end of said arm in a closed path, a master gear on said spindle, rack teeth on opposite sides of said master gear whereby said master gear will be moved alternately into engagement with said rack teeth, and means to feed the blank relative to said tool.

9. A gear tooth generating machine comprising in combination, a base, a cutting tool thereon, work supporting means comprising a spindle movable "to any position while its axis extends always in the same direction, an arm for mounting the work spindle, means to actuate one end of said arm in a closed path, a master gear on said spindle adapted to be actuated at a point intermediate of said arm, a slide, rack teeth provided on said slide and positioned on opposite sides of said master gear whereby said master gear will be moved alternately into engagement with said rack teeth, and means to move said slide to feed the blank relative to said tool.

10. A machine for generating the tooth curves of gears comprising in combination, a base, a cutting wheel rotatably mounted thereon, a work spindle supported on said base so that it may move in any direction while its axis is maintained in parallel position, a movable slide mounted on said base, means carried by said slide limiting the bodily movements of said work spindle, means to reciprocate the slide to effect feeding movements of a gear blank thereon relative to said cutting wheel, and means to actuate the work spindle within a closed path.

11. A machine for generating tooth curves of gears comprising in combination, a base, a cutting wheel rotatably mounted thereon, a work spindle supported on said base so that it may move in any direction while its axis is maintained in parallel positions, a movable slide on said base, means carried by said slide for limiting the bodily move ments of said work spindle, cam means to move said slide to effect feeding movements of a gear blank relative to said cutting wheel, and cam means to elfect bodily movements of the work spindle within a closed path.

In testimony whereof, I hereto aflix my signature.

ARTHUR L. VVILDER. 

